feat: subcommands prototype implementation (#19)

examples/escript/example.ex

@@ -18,6 +18,10 @@ defmodule Escript.Example do
   defcommand :foo, required: true, type: :string, doc: "Command that receives a string as argument and prints it."
   defcommand :fizzbuzz, type: {:enum, ~w(fizz buzz)a}, doc: "Fizz bUZZ", required: true
 
+  defcommand :foo_bar, type: :null, doc: "Teste" do
+    defcommand :foo, default: "hello", doc: "Hello"
+    defcommand :bar, default: "hello", doc: "Hello"
+  end
 
   @impl true
   def version, do: "0.1.0"
@@ -35,6 +39,16 @@ defmodule Escript.Example do
     IO.puts("fizz")
   end
 
+  def handle_input(:foo_bar, %{value: _, subcommand: :foo}) do
+    # do something wth "foo" value
+    :ok
+  end
+
+  def handle_input(:foo_bar, %{value: _, subcommand: :bar}) do
+    # do something wth "bar" value
+    :ok
+  end
+
   Nexus.help()
   Nexus.parse()
 

lib/nexus.ex

@@ -46,8 +46,9 @@ defmodule Nexus do
   defmacro __using__(_opts) do
     quote do
       Module.register_attribute(__MODULE__, :commands, accumulate: true)
+      Module.register_attribute(__MODULE__, :subcommands, accumulate: true)
 
-      import Nexus, only: [defcommand: 2]
+      import Nexus, only: [defcommand: 2, defcommand: 3]
       require Nexus
 
       @behaviour Nexus.CLI
@@ -65,11 +66,33 @@ defmodule Nexus do
   """
   @spec defcommand(atom, keyword) :: Macro.t()
   defmacro defcommand(cmd, opts) do
-    quote do
+    quote location: :keep do
       @commands Nexus.__make_command__!(__MODULE__, unquote(cmd), unquote(opts))
     end
   end
 
+  defmacro defcommand(cmd, opts, do: ast) do
+    subcommands = build_subcommands(ast)
+
+    quote location: :keep do
+      @commands Nexus.__make_command__!(
+                  __MODULE__,
+                  unquote(cmd),
+                  Keyword.put(unquote(opts), :subcommands, unquote(subcommands))
+                )
+    end
+  end
+
+  defp build_subcommands({:__block__, _, subs}) do
+    Enum.map(subs, &build_subcommands/1)
+  end
+
+  defp build_subcommands({:defcommand, _, [cmd, opts]}) do
+    quote do
+      Nexus.__make_command__!(__MODULE__, unquote(cmd), unquote(opts))
+    end
+  end
+
   @doc """
   Generates a default `help` command for your CLI. It uses the
   optional `banner/0` callback from `Nexus.CLI` to complement

lib/nexus/command.ex

@@ -12,11 +12,18 @@ defmodule Nexus.Command do
           required: boolean,
           name: atom,
           default: term,
-          doc: String.t()
+          doc: String.t(),
+          subcommands: [Nexus.Command.t()]
         }
 
   @enforce_keys ~w(module type name)a
-  defstruct module: nil, required: true, type: :string, name: nil, default: nil, doc: ""
+  defstruct module: nil,
+            required: true,
+            type: :string,
+            name: nil,
+            default: nil,
+            doc: "",
+            subcommands: []
 
   @spec parse!(keyword) :: Nexus.Command.t()
   def parse!(attrs) do

lib/nexus/command/input.ex

@@ -4,10 +4,10 @@ defmodule Nexus.Command.Input do
   on commands dispatched
   """
 
-  @type t :: %__MODULE__{value: term, raw: binary}
+  @type t :: %__MODULE__{value: term, raw: binary, subcommand: atom}
 
   @enforce_keys ~w(value raw)a
-  defstruct value: nil, raw: nil
+  defstruct value: nil, raw: nil, subcommand: nil
 
   @spec parse!(term, binary) :: Nexus.Command.Input.t()
   def parse!(value, raw) do

lib/nexus/parser.ex

@@ -14,8 +14,28 @@ defmodule Nexus.Parser do
     |> String.trim_leading()
     |> parse_command(cmd)
     |> case do
-      {:ok, input} -> input
-      {:error, _} -> raise Error, "Failed to parse command #{inspect(cmd)}"
+      {:ok, input} ->
+        input
+
+      {:error, _} ->
+        raise Error, "Failed to parse command #{inspect(cmd)}"
+
+      :error ->
+        raise Error,
+              "Failed to parse command #{inspect(cmd)} with subcommands #{inspect(cmd.subcommands)}"
+    end
+  end
+
+  defp parse_subcommand(input, cmd) do
+    case parse_command(input, cmd) do
+      {:ok, input} -> {:halt, {:ok, Map.put(input, :subcommand, cmd.name)}}
+      {:error, _} -> {:cont, :error}
+    end
+  end
+
+  defp parse_command(input, %Command{type: :null, subcommands: [_ | _] = subs} = cmd) do
+    with {:ok, {_, rest}} <- literal(input, cmd.name) do
+      Enum.reduce_while(subs, :error, fn sub, _acc -> parse_subcommand(rest, sub) end)
     end
   end
 

mix.exs

@@ -1,7 +1,7 @@
 defmodule Nexus.MixProject do
   use Mix.Project
 
-  @version "0.3.1"
+  @version "0.4.0"
   @source_url "https://github.com/zoedsoupe/nexus"
 
   def project do
@@ -40,7 +40,7 @@ defmodule Nexus.MixProject do
       licenses: ["WTFPL"],
       contributors: ["zoedsoupe"],
       links: %{"GitHub" => @source_url},
-      files: ~w(lib/nexus lib/nexus.ex LICENSE README.md mix.*)
+      files: ~w(lib/nexus lib/nexus.ex LICENSE README.md mix.* examples)
     }
   end